title: Gender dimorphism in skeletal muscle leptin receptors, serum leptin and insulin sensitivity.
abstract: To determine if there is a gender dimorphism in the expression of leptin receptors (OB-R170, OB-R128 and OB-R98) and the protein suppressor of cytokine signaling 3 (SOCS3) in human skeletal muscle, the protein expression of OB-R, perilipin A, SOCS3 and alpha-tubulin was assessed by Western blot in muscle biopsies obtained from the m. vastus lateralis in thirty-four men (age = 27.1+/-6.8 yr) and thirty-three women (age = 26.7+/-6.7 yr). Basal serum insulin concentration and HOMA were similar in both genders. Serum leptin concentration was 3.4 times higher in women compared to men (P<0.05) and this difference remained significant after accounting for the differences in percentage of body fat or soluble leptin receptor. OB-R protein was 41% (OB-R170, P<0.05) and 163% (OB-R128, P<0.05) greater in women than men. There was no relationship between OB-R expression and the serum concentrations of leptin or 17beta-estradiol. In men, muscle OB-R128 protein was inversely related to serum free testosterone. In women, OB-R98 and OB-R128 were inversely related to total serum testosterone concentration, and OB-R128 to serum free testosterone concentration. SOCS3 protein expression was similar in men and women and was not related to OB-R. In women, there was an inverse relationship between the logarithm of free testosterone and SCOS3 protein content in skeletal muscle (r = -0.46, P<0.05). In summary, there is a gender dimorphism in skeletal muscle leptin receptors expression, which can be partly explained by the influence of testosterone. SOCS3 expression in skeletal muscle is not up-regulated in women, despite very high serum leptin concentrations compared to men. The circulating form of the leptin receptor can not be used as a surrogate measure of the amount of leptin receptors expressed in skeletal muscles.
authors.affiliation: Department of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, Spain.
authors.forename: Borja
authors.initials: B
authors.lastname: Guerra
authors.forename: Teresa
authors.initials: T
authors.lastname: Fuentes
authors.forename: Safira
authors.initials: S
authors.lastname: Delgado-Guerra
authors.forename: Amelia
authors.initials: A
authors.lastname: Guadalupe-Grau
authors.forename: Hugo
authors.initials: H
authors.lastname: Olmedillas
authors.forename: Alfredo
authors.initials: A
authors.lastname: Santana
authors.forename: Jesus Gustavo
authors.initials: JG
authors.lastname: Ponce-Gonzalez
authors.forename: Cecilia
authors.initials: C
authors.lastname: Dorado
authors.forename: José A L
authors.initials: JA
authors.lastname: Calbet
mesh_terms: D000328:Adult; D002352:Carrier Proteins; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood*; D020738:Leptin / Q000097:blood*; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry*; D000070778:Perilipin-1; D010750:Phosphoproteins / Q000032:analysis; D054411:Receptors, Leptin / Q000032:analysis*; D012727:Sex Characteristics; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000032:analysis; D013739:Testosterone / Q000097:blood; D014404:Tubulin / Q000032:analysis
chemical_list: D002352:Carrier Proteins; D007328:Insulin; D020738:Leptin; D000070778:Perilipin-1; D010750:Phosphoproteins; D054411:Receptors, Leptin; C106644:SOCS3 protein, human; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D014404:Tubulin; D013739:Testosterone